| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device, a process cartridge and an image forming device capable of obtaining high transfer efficiency, restraining the shaving of a photoreceptor and faulty transfer such as transfer middle omission, avoiding an image defect such as fogging or the like even in the case of long- term use, preventing the lowering of image density at the beginning of the user, and always obtaining stable high quality and high density. SOLUTION: This developing device prepares magnetic developer whose circularity obtained by circularity a=L0/L (provided that L shows the peripheral length of the projected image of a particle and L0 shows the peripheral length of a circle having the same projection area as a particle image) is >=0.970 and <=0.995, and saturation magnetization under 79.6 kA/m (1,000 oersted) is >=10 Am2/kg (emu/g) and <=50 Am2/kg. The device is provided with a partition member from an upper part in a developer container on the developing sleeve side in the developer container. |
